Guide-roll arrangement for continuous casting



United States Patent inventor Francis Gallucci North HuntingdonTownship, Westmoreland County. Pa.

Appl. No. 699,150

Filed Jan. 19, 1968 Patented Dec. 29, 1970 Assignee United States SteelCorporation a corporation of Delaware GUIDE-ROLL ARRANGEMENT FORCONTINUOUS CASTING 5 Claims, 5 Drawing Figs.

US. Cl 164/282, 198/ l 67 int. Cl 822d 11/12 Field of Search 164/82,

273, 282, 283, 83; 198/202, l67recent [56] References Cited UNITEDSTATES PATENTS l,678.925 7/1928 Tackaberry 198/202 1,980,777 1 l/l 934Zollinger l98/202X 3,263,284 8/1966 Orr et al. (l64/282UX) 3,338,2978/1967 Foldessy... l64/282X 339L725 7/1968 Rossi l64/283X PrimaryExaminer-J. Spencer Overholser Assistant Examiner-R. Spencer AnnearAttorney-Walter P. Wood ABSTRACT: In a continuous-casting machine theguide rolls, which conduct the solidifying slab from the mold to thepinch rolls, conventionally are all idlers. The invention incorporatestwo sets of power-driven rolls among the guide rolls. The power-drivenguide rolls, in conjunction with the usual powerdriven pinch rollsbelow, control the forces on the descending slab and its movement as itsolidifies.

PATENTED UEB29 I978 SHEET 1 OF 2 CCCOOCCO CCCCCCCC INVENTUR FRANCISGALLUCC/ 0km?) 76%1L,

Attorney PATENTEDUEE29I970 3550 721 sum 2 [IF 2 INVENTOR FHA/V675GALLUCC/ GUIDE-ROLLARRANGEMENT FOR CONTINUOUS. CASTING This inventionrelates to an improved guide-roll arrangement for a continuous-castingmachine, and to a method of controlling forces on a continuously castslab.

The form of continuous-casting machine in which my guideroll arrangementand method are used includes a water-cooled mold open at both ends,trains of vertically spaced opposed pairs of guide rolls below the mold,a set of power-driven pinch rolls below the guide rolls, and a curvedcasting guide below the pinch rolls. Before a casting operation begins,a starter bar is inserted upwardly through the pinch rolls and guiderolls to the mold. A stream of molten metal is poured through the moldinto contact with the top of the starter bar, which descends through theguide rolls and pinch rolls ahead of the resulting slab. As the slabpasses the guide rolls, water sprays are applied to its surface to aidin solidifying it. Initially the leading end of the slab attaches itselfto the top of the starter bar, but the starter bar is disconnected asthe slab reaches the pinch rolls. At first the pinch rolls restraindescent of the starter bar, but after the slab is part way through theguide rolls, the pinch rolls propel the starter bar and slab.

After the starter bar is disconnected, bending rolls within the calforces on the slab until it reaches the pinch rolls. Since only theouter portions of the slab solidify ahead of the pinch rolls, the slabis easily damaged by excessive pressure on its sides or excessivecompressive'force from above or too much tension.

An object of my invention is to provide an improved guiderollarrangement in which at least one set of guide rolls are power drivenand cooperate with the pinch rolls to control forces on a descendingslab. I

A further object is to provide an improved guide-roll arrangement inwhich one or more sets of power-driven rolls bear on a descending slabahead of the pinch rolls under a controlled pressure and at a controlledtorque, thereby regulating the forces on the slab to minimize thepossibility of damage, and also to assure that the starter bar isproperly disconnected from the slab.

A further object is to provide an improved method of controlling theforces on a descending slab ahead of the pinch rolls.

In the drawings:

FIG. 1 is a diagrammatic side elevational view of a portion of acontinuous-casting machine equipped with my improved arrangement ofguide rolls;

FIG. 2 is a horizontal section on a larger scale on line II-II of FIG.I; I

I FIG. 3 is an elevational view of a portion of the structure from theright of FIG. 2; v

' FIG. 4 is a vertical section on line IV-IV of FIG. 2; and

FIG. 5 is a vertical section on line V-V of FIG. 2.

FIG. 1 shows a continuous-casting machine which includes an open endedmold 10, four trains of vertically spaced, opposed pairs of idler guiderolls l2, I3, 14 and 15 below the mold, power-driven pinch rolls 16below the guide rolls, a casting guide 17 below the pinch rolls, and astarter bar 18. The casting guide is equipped with bending rolls 19.These parts can be of a known construction, for example, as shown in theaforementioned Foldessy patent; hence I have not shown them in detail.The machine of course includes other conventional parts which I have notshown, since they are not involved in the present invention. A slab S isshown descend ing through the machine. i

In accordance with my invention, I interpose an upper set ofpower-driven guide rolls 20 between the. two trains of idler guide rollsl2 and 13, and a lower set of power-driven guide rolls 21 between thetwo trains of idler guide rolls l4 and 15. The two sets of power-drivenrolls 20 and 21 are of like construction and similarly mounted; hence Ishow and describe only the set 20 and their mounting in detail.

As shown in FIGS. 2, 4 and 5, the machine has fixed housing members 22and 23 at opposite sides. The housing members have horizontal shoulders24 on which rest opposed frames 25 and 26 for supporting the respectiverolls 20. The frames are held in position by keepers 27 and bolts 28which extend through the housing members and keepers. The two frames andthe parts carried by each are of like construction; hence I describe indetail only the frame 25. Frame 25 includes a pair of opposed channels30, inner and outer transverse bars 31 and 32 rigidly attached at theirends to the channels, and gussets 34 between the end portions of thebars. Preferably the outer transverse bar 32 is bowed outwardly. Islidably mount a A pair of opposed bearing chocks 35 in channels 30 andjournal the roll 20 in these chocks. Roll 20 has right and left-handhelical grooves 37 extending from its opposite ends toward the middle. Ijoin a drive shaft 38 to one end of roll 20 through a detachablecoupling 39.

Two sets of backup rolls 42 of four to each set are journaled infixtures 43 and bear against roll 20. Each fixture 43 is slidablymounted on a respective pair of studs 44 fixed to the inner transversebar 31. Pairs of spaced-apart nuts 45 are threadedly engaged with thestuds to limit movement of the fixtures. Each fixture has a pair ofplungers 46 pivoted thereto and extending through respective openings inbar 31 and a guide 47 fixed to the gusset 34. A leaf spring 48 abuts theends of the two plungers 46. Cap screws 49 are threadedly engaged withthe outer transverse bar 32 and abut the opposite face of the leafspring. Cover plates 50 span the space between the inner and outer bars31 and 32 above and below the bars and serve as guides for the spring48. Thus by turning the cap screws 49 I can initially adjust thepressure with which the backup rolls 42 bear against the roll 20. Thispressure remains constant until a further adjustment is made.

A pair of opposed stops 52 are fixed to the inner faces of the housingmembers 22 and 23 between the channels 30 of the two frames 25 and 26.The channel 30 of frame 25 abuts these stops. I interpose removablespacers 53 of rectangular cross section and removable spacers 54 ofangular cross section between the channel of frame 26 and stops 52. Byproper selection of spacers, I control the spacing of rolls 20 inaccordance with the slab thickness.

To remove the set of rolls 20 from the machine, it is only necessary touncouple the drive shafts 38 from the roll necks and remove keepers 27and bolts 28. The two frames 25 and 26 then can slide freely from thehousing members 22 and 23. The latter have slots 55 (FIG. 5) throughwhich the roll necks extend in order not to interfere with such removalAccording to my control method, I drive the guide rolls 20 and 21 with aforce such that the torque on each set is about 5 to 40 percent of thetorque on the pinch rolls 16. The grooves 37 in the surface of thedriven guide rolls hold the solidifying slab S. In this manner the twosets of driven guide rolls 20 and 21 and the pinch rolls 16 cooperate tominimize forces in the section of the slab therebetween. This sectionnormally is in considerable tension once the leading end of the slabdescends part way through the guide rolls, although ideally it would befree of longitudinal forces (tension or compression). When my inventionis employed, the tension is small. This is of particular importance atthe time the starter bar 18 is disconnected. My preferred starter'barhasa separable chill plate which is mechanically detached from the bar andremains with the slab, as shown or example in my earlier copendingapplication Ser. No. 616,103, filed Feb. 14, 1967 (now US. Pat. No.3,448,789 This type of starter bar can be disconnected properly onlywhen the tensile forces are not excessive. By initially adjusting thecap screws 49., I control the constant pressure with which the drivenguide rolls bear against the slab.

While I have shown and described only a single embodiment of myinvention, it is apparent that modifications may arise. Therefore, I donot wish to be limited to the disclosure set forth but only by the scopeof the appended claims.

I claim:

1. In a continuous-casting machine which includes an open ended mold,trains of vertically Spaced opposed pairs of idler guide rolls belowsaid mold, a set of power-driven pinch rolls below said guide rolls, anda curved casting guide below said Jinch rolls, the the combinationtherewith of an improved guide roll arrangement comprising at least oneopposed pair of ower-driven guide rolls among said idler guide rolls, anop- )osed pair of frames in said machine, bearing chocks mounted n saidframes, said power-driven guide rolls being joumaled in aid chocks,backup rolls mounted in said frame and engaging aaid power-driven guiderolls, and initially adjustable spring neans mounted on said frame forapplying a constant pressure said backup rolls, said power-driven guiderolls being cooperable with said pinch rolls to control forces on a slabas it travels therebetween.

2. A guide-roll arrangement as defined in claim 1 in which there are twopairs of power-driven guide rolls.

3. A guide-roll arrangement as defined in claim I in which each of saidframes includes inner and outer spaced apart transverse bars, fixturesslidably supported on said inner bar, said backup rolls being journaledin said fixtures, and spring means bearing against said fixtures, andcap screws thradedly engaging said outer bars 'and I bearing againstsaid s'prih'g means.

4. A guide-roll arrangementas defined in claim 1 in which said framesare slidably removable from said machine.

5. A guide-roll arrangement as defined in claim I in which the surfacesof said power-driven guide rolls have right and left hand helicalgrooves extending from opposite ends toward the middle.

